3D Tiles 1.1 Photogrammetry Classification

<!--
  示例：倾斜摄影的分类着色
  说明：三分类建筑体块按类别取色，并用 HTML 图例标出类别与颜色的对应关系
  核心逻辑：分类值查色表 → Entity 盒体 material → 相机俯视
  依赖：CesiumJS 1.121 · jsDelivr CDN
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>倾斜摄影的分类着色</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Widgets/widgets.css">
<style>
  html,body{height:100%;margin:0}
  body{background:#0e1116;color:#e6e8ec;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  #c{height:100%}
  .tip{position:absolute;left:12px;top:12px;z-index:5;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:8px 12px;font-size:12px;color:#a2a9b6;max-width:320px;line-height:1.6}
  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
  .legend{position:absolute;right:12px;bottom:12px;z-index:5;display:flex;gap:12px;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:6px 10px;font-size:12px;color:#a2a9b6}
  .legend i{display:inline-block;width:10px;height:10px;border-radius:2px;margin-right:5px;vertical-align:middle}
</style>
</head>
<body>
<div id="c"></div>
<div class="tip">右下角图例与建筑颜色一一对应。分类值在这里由行列序号生成，换成真实数据时读取要素属性即可。</div>
<div class="legend">
  <span><i style="background:#4d7cff"></i>住宅</span>
  <span><i style="background:#ffb44d"></i>商业</span>
  <span><i style="background:#3ecf8e"></i>绿地</span>
</div>
<script src="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Cesium.js"></script>
<script>
(function () {
  'use strict';

  var viewer = new Cesium.Viewer('c', {
    baseLayer: false,
    baseLayerPicker: false, geocoder: false, homeButton: false,
    sceneModePicker: false, navigationHelpButton: false,
    animation: false, timeline: false, fullscreenButton: false,
    infoBox: false, selectionIndicator: false
  });

  var scene = viewer.scene;
  scene.globe.baseColor = Cesium.Color.fromCssColorString('#1c2733');
  scene.backgroundColor = Cesium.Color.fromCssColorString('#0e1116');
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  var west = 116.383, south = 39.900, east = 116.399, north = 39.914;

  var legend = { '住宅': '#4d7cff', '商业': '#ffb44d', '绿地': '#3ecf8e' };
  var keys = Object.keys(legend);

  viewer.entities.add({
    polygon: {
      hierarchy: new Cesium.PolygonHierarchy(
        Cesium.Cartesian3.fromDegreesArray([west, south, east, south, east, north, west, north])
      ),
      height: 0,
      material: Cesium.Color.fromCssColorString('#1b232e')
    }
  });

  var seed = 9;
  function rnd() { seed = (seed * 9301 + 49297) % 233280; return seed / 233280; }

  for (var r = 0; r < 7; r++) {
    for (var c = 0; c < 7; c++) {
      var kind = keys[(r * 3 + c) % 3];
      var h = 10 + rnd() * 46;
      var w = 16 + rnd() * 14;
      viewer.entities.add({
        position: Cesium.Cartesian3.fromDegrees(west + 0.0012 + c * 0.0021,
                                                south + 0.0012 + r * 0.00185, h / 2),
        box: {
          dimensions: new Cesium.Cartesian3(w, w, h),
          material: Cesium.Color.fromCssColorString(legend[kind]),
          outline: true,
          outlineColor: Cesium.Color.fromCssColorString('#0b0f14')
        }
      });
    }
  }

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3825, 39.8970, 1500),
    orientation: { heading: Cesium.Math.toRadians(18), pitch: Cesium.Math.toRadians(-30), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>